SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b8ab901719e336fd6cdbda778cf2f310973ebdfe351c2da16a513032213a9e6' 
  AND token = 'tr0ghezCOaP7TlTpPLFMImV20hyIfIeD7WWStL5Z11Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}